Morphological Effects of Root Pruning and Wrenching White Spruce Transplants
Abstract The principal objective of this research was to evaluate the effect of root pruning followed by wrenching on the morphological quality of 2 + 2 white spruce transplant stock during the final year on the nursery. In 1984, white spruce transplants were root pruned: (1) before shoot elongation; (2) during elongation; and (3) after elongation, followed by root wrenching at 28-day intervals until September (4, 3, and 2 times, respectively). In 1985, similar stock was root pruned before shoot elongation and (1) root wrenched at 21-day intervals (4 times), and (2) root wrenched periodically (twice). In both years, height and root collar diameter growth were monitored throughout the season. In the fall, morphological quality was assessed and bud samples were collected to determine the effects of root conditioning on primordia development. Root conditioning modified the morphology of stock in both years by reducing height and root collar diameter and inducing the development of a compact fibrous root system. Early season root pruning followed by wrenching at regular intervals throughout the growing season had the most effect on shoot and root morphology. Differences in results between years were attributed to environment. North. J. Appl. For. 5:245-247, December 1988.